Control mechanism



Sept. 4, 1945. H. E. MALONE CONTROL MECHANISM INVENTOR. HUMER EMALUNE W?wTTORNEY.

2 Sheets-Sheet l l 4 9 l Y B c m a m w m 1 & n a 1 F 8 .l 3 m 8 WW 9 5 8o w 5 BIHETAL Sept. 4, 1945. H. E. MALONE 2,383,982

' CONTROL MECHANISM Filed Dec. 26, 1941 2 Sheets-Sheet 2 INVENTOR.

BY HUMER E- MALONE WF$s ATTORNEY.

Patented Sept. 4, 1945 CONTROL MECHANISM Homer E. Malone, Milwaukee,Wis., assignor to Perfex Corporation, Milwaukee, Wis., a corporation ofWisconsin Application December 26, 1941, Serial No. 424,395

12 Claims.

This invention relates in general to automatic controls and moreparticularly to controls of the type adapted for wall mounting. It is anobject of this invention to provide a wall mounting automatic controlinstrument which is simple and rugged in construction, which is neat andattractive in exterior appearance, which may be easily installed, andwhich provides for protection of the various working parts thereof.

More particularly, it is an object of this invention to provide a wallmounting automatic control instrument in which all of the parts aresecured to the inside of the cover, thus forming a single control unitin which the cover serves as a base, the cover also serving to insureprotection of the working parts of the instrument prior to and duringinstallation of the instrument.

A further object of the invention is the provision of a wall mountingthermostat in which transmission of heat from the wall to the thermalelement by conduction is reduced to a minimum, thus rendering thecontrol more quickly responsive to changes in air temperature.

Another object of the invention is the provision of a simple adjustingmechanism for permitting a manual adjusting member to be spaced from themechanism operated thereby.

Other objects of the invention will become apparent from the followingdescription and appended claims.

For full disclosure of this invention, reference is made to thefollowing detailed description and to the accompanying drawings, inwhich Fig. l is a side view, partly in section, of a room thermostatembodying the present invention;

Fig. 2 is a rear view partly in section;

Fig. 3 is a. sectional view taken on line 3-3 of Fig.2;

Fig. 4 is a front view of the sub-base member:

Fig. 5 is a front view of the wall plate, and showing the cover insection;

Fig. 6 is a front view of the thermostat cover;

Fig. '7 is a sectional view taken on line 1-1 of Fig. l; and in whichFig. 8 is a fragmentary sectional view showing the differentialadjustment mechanism.

Referring now to Figs, 1 and 5, reference character l indicates a wallplate having rearwardly projecting bosses 2 for spacing the wall platefrom the wall upon which it is mounted by suitable screws which extendthrough these bosses. The wall plate is off-set at 3 to provide an upperoff-set portion 4 having a wide U-shaped opening 5 therein. This upp rportion 4 has its legs 6 and I on opposite sides of opening 5 bentinwardly at 8 and 9 for engaging the wall and steadying the wall platethereon. The upper section 4 of the wall plate also carries a terminalpanel in of insulating material, this terminal panel having an opening Il at its top for permitting wires extending from the wall to be broughtto the front of the panel. The terminal panel III also carries a pair ofcontact brackets l2 and I! having flexible, downwardly and outwardlyextending contact arms M and I5, and terminal screws l6 and H. Thterminal panel III also carries a pair of stop members l8 and I9, thesestop members extending through openings in the spring members it and I5and having head portions which limit movement of the spring members awayfrom the wall plate.

Mounted on the ,wall plate I is a cover 20 for the instrument, thiscover having a front wall 2 I, side walls 22 and 23, and end walls 24and 25, the end walls being provided with openings 28 and 21 forpermitting air in the room to circulate through the cover. The upper endof the cover may be held in place by spring members 28 and 29 which areattached by suitable brackets to the wall plate and which engage therear face of opening 26. The lower end of the cover 20 may be secured tothe wall plate I by means of an ear 30 formed on the wall plate andreceiving a screw 3| which passes through an opening in the bottom ofthe cover.

When the present invention is embodied in room thermostat construction,it is preferable to provide the cover with a slot 32 for receiving athermometer element 33 which is mounted on the rear of the cover by aspring member 34 secured to the cover by screw 35.

Mounted within the cover 20 is a sub-base 38, this sub-base being spacedfrom the front wall of the cover by means of bosses 39 formed on thefront of the cover adjacent the side walls, these bosses receivingscrews 4| and 42 which pass through sub-base 38. The sub-base 38 is alsosteadied inside of the cover by additional bosses 43 and 44 locatedabove bosses 39. This arrangement in which the sub-base is supportedonly at its mid-portion in the cover avoids distortion of the sub-basewhen screwed tightly to the cover.

The sub-base 38 is preferably of molded construction, its front facebeing hollowed out as at 45. The rear face of the sub-base is providedwith a boss near its mid-portion, this boss carrying a spring hinge 46which is clamped thereto by a clamping plate 41. The other end of thespring hinge clamped between a U-shaped bimetal element as and anadjusting arm 48 having slotted end receiving a calibrating screw :38which rides upon a helical cam member The U-shaped bimetal element 48 atits upper end carries an armature bracket 52. Between the armaturebracket 52 and element 48 is clamped a pin 53 carrying a twin contactbracket ti l, this pin being steadied at its upper end by an inwardlybent portion of the armature bracket. The twin contact bracket 54carries a rigid arm 55 intermediate its ends, this arm 85 having anoff-set portion and carrying a movable contact 55 at one end. The arm 85also carries a flexible arm 51 which at its other end carries a secondmovable contact 58/ The movable contacts 58 and 58 cooperaterespectively with fixed contact studs 8! and 62 which are mounted uponthe sub-base 38. This sub-base also carries a permanent magnet 83 whichis secured thereto by means of a screw 64 extending from the front ofthe sub-base and engaging a clamping plate 85. The clamping plate 41 forthe spring hinge carries a heater 88 which is engaged by a slider 61carried by the clamping plate 85 for the permanent magnet. It will beapparent that the thermostatic element 48 serves to actuate the controlmeans comprising the fixed and movable contacts upon change intemperature, the snap action means, consisting of the permanent magnetand armature, imparting snap action to the engagement and disengagementof the contacts. '11; will also be apparent that rotation of the helicalcam it will vary the control point of the instrument. No novelty isclaimed in the particular construction of the thermostatic element, twincontact construction, or adjustable heater construction, this generalarrangement being shown in the Lindemann Patent 2,250,135, dated July22, 1941. For a. more complete description of the construction andoperation of the bimetal element and switching mechanism, reference ismade to this Lindemann patent.

The fixed contact stud 62 is carried by a bracket '18 mounted upon thesub-base, this bracket being generally L-shaped and including a leg Hwhich extends rearwardly into engagement with the contact spring l8carried by the wall plate I. Thus when the thermostat cover is in placeon the wall plate the terminal screw [1 is electrically connected to thefixed contact stud 82.

The fixed contact stud 8| is carried by a bracket 18 which is joined tothe clamping member 85 of the permanent magnet by an outwardly extendingportion 18. Thus the contact stud 8| is electrically connected with theslider 81 which is mounted on member 88 and which engages the heater 88.The heater 88 is electrically insulated from the clamping plate 41 andis connected electrically to a bracket 11 which is mounted on thesub-base 38, this bracket having a rearwardly extending leg I8 whichengages the spring blade I4 when the cover is in place on the wallplate. Thus when the movable contacts 88 and 58 are in engagement withtheir respective fixed contact studs, a circuit is completed from theterminal screw I! through spring member l5, contact leg 1|, stud 82,movable contact 88, flexible arm 51, movable contact 58, contact stud8|, bracket 1!, connecting member 18, clamping plate 88, wiper 61,heater 88, bracket 11, connector leg 18 and spring blade I to terminalscrew I8. When the movable contacts are Q18- shaft.

engaged from the fixed contacts, the above traced circuit is of coursebroken.

The helical cam member 5| is preferably formed of insulation materialand is secured to a shaft which extends through a hole formed in thesub-base 38 and also through an enlarged hole 8! in the front wall ofthe cover. The front end of the shaft 88 is slotted as at 82 and carriesa control point adjusting knob 88 which extends through the opening Ill.The knob 83 is formed with a flattened, rearwardly projecting portion 84which fits into the slot 82 in the shaft 80. This insures that the knob83 must be positioned correctly on the shaft 88 so that the pointer 88(Fig: 6) will be positioned properly with respect to the helical cam 5|.The pointer 85 on the knob 83 cooperates with indicia 86 carried by thecover for indicating the control point setting of the instrument. Theknob 88 is fastened to the shaft 80 by means of a set screw 81 whichserves to spread the split section of the shaft into tight engagementwith the knob. Preferably the helical cam 5| is formed at its rear toreceive a disc 88 which is held in snug engagement between the cam andsub-base by a spring member 88. The disc 88 cooperates with a lug 80mounted on the rear of the sub-base by a screw 8| for forming a lock toprevent unauthorized persons from changing the control point adjustmentof the instrument. It will be apparent that when the screw 8| istightened, the lug 88 will prevent rotation of the disc 88, which inturn prevents rotation of the cam 5|. When the screw 8! is loosened thehelical cam 5! is free to rotate.

It is desirable to provide for adjusting the duration of the "on periodsof the thermostat. Preferably this adjustment should be accessible tothe home owner so that he may vary the "on periods to secure optimumcontrol without requiring any knowledge of the instrument mechanism. Toobtain this result, the fixed contact stud 82 is threaded loosely intothe bracket 18. It will be apparent that rotation of the stud 82 willmove the fixed contact in and out and thus vary the distance between thearmature and magnet when the contacts are engaged. This varies theamount of force required to be built up within the thermostatic elementbefore the contacts are disengaged. Inasmuch as it requires time for theheater 88 to build up an opening force within the thermostatic element,it follows that adjustment of the stud 82 varies the thermostat onperiod. The outer end of the stud 62 is attached to a lever 82 by ascrew as shown. Preferably a spring 88 surrounds the stud 82 forresisting rotation thereof, thus tending to retain the stud 82 inadjusted position. The free end of the lever 82 is attached to a. link84, the other end of which is attached to a second lever 88. The lever88 is slotted at 88 and fits over a coinciding portion formed on a shaft81 which extends through the sub-base 88. The link 85 may be held ontothe shaft 81 in any suitable manner as by peening. The shaft 8'! isformed with a screw head at its inner end. Its other end is formedslightly flattened as at 88 and receives an adjusting knob 88 whichextends through an opening in the front of the cover. The knob 88 isprovided with an opening which flts tightly on the portion 88 of theshaft 81, this opening being flattened similar to the portion 88 so asto insure proper positioning of the knob on the Preferably the knob 88is held on the shaft by friction, the shaft being splined at its end.The knob 88 canies a pointer [88 which ing an opening for such knob. Thedifferential adjustment may then be actuated by removing the cover fromthe wall plate and rotating the shaft 91 with a screw driver. Preferablythe subbase 38 is provided with indicia ill! for indicatin thedifferential adjustment.

From the foregoing description it will be apparent that the wall plate Iis formed so as to be spaced from the wall so as to reduce conduction ofheat between the wall plate and wall to a minimum. It will also be seenthat the only metallic heat path from the wall plate to the bimetalelement consists of the spring contact members II and I and the contactlegs or brackets Ii and 78. This path for heat conduction is very longand of very small cross-sectional area. As a result, conduction of heatbetween the wall or wall plate and the thermostatic element is reducedto a minimum. This permits the thermostatic ele- I ment 48 to followchanges in room temperature more rapidly than if the element were inbetter heat conducting relationship with the wall, As a result thearrangement provided by this invention provides a more sensitive wallmounting control.

It should also be apparent that the instrument provided by the presentinvention is very easy to install. All that is required is the mountingof the wall plate on the wall and connection of the control wires to theterminal screws, the thermostat cover then being secured in place on thewall plate for completing the installation. It should further beapparent that all of the working parts of the instrument are at alltimes completely within the cover and consequently protected by thecover. This insures against possible damage to the instrument duringinstallation. It will be further apparent that the present inventionprovides a construction which is neat and attractive in exterior aparance, and which may be readily replaced if necessary.

While I have shown and described a preferred form of the invention, itis obvious that many changes may be made from the device disclosedwithout departing from the invention. Accordingly it is desired to belimited only by the scope of the appended claims.

What is claimed is:

1. In a control device for mounting on a wall. the combination of, awall plate carrying termi nals for electrical wiring and adapted to bemounted on a wall, a cover for the control device adapted for mountingon said wall plate, an elongated sub-base mounted on the inside of thecover and being attached to said cover only near the mid-portion of saidsub-base, a condition responsive switching mechanism secured to saidsub-base, and means for securing the cover directl to the Wall plateindependently of the sub-base and for connecting the switching mechanismto the terminals on said wall plate.

2. In a control device for mounting on a wall, the combination of, awall plate carrying terminals for electrical wiring and adapted to bemounted on a wall, a cover for the control device adapted for mountingon said wall plate, a sub-base mounted on the inside of the cover havingone side facing the rear face of the cover and its other side facing thewall plate, a condition responsive device on the side of the sub-basefacing the wall plate, said condition responsive device havin oneportion thereof secured to the sub-base and actuating a first electricalcontact, a. contact bracket secured to the sub-base and carrying asecond electrical contact arranged for cooperation with said firstcontact, said contact bracket including an electrical conducting portionextending toward the wall plate, a second bracket mounted on saidsub-base and having an electrical conducting portion electricallyconnected to said first contact and extending toward said wall plate,and resilient contact means on the wall plate arranged for engagementwith said brackets and connected to said terminals.

3. In a control device for mounting on a wall, the combination of, awall plate carrying terminals for electrical wiring and adapted to bemounted on a wall, a cover for the control de-- vice, means for securingthe cover directly to said wall plate, a pair of stationary contactsmounted on the inside of the cover, means including condition responsivemeans mounted on the inside of the cover for electrically bridging orunbridging said stationary contacts, a first bracket mounted on theinside of the cover, said bracket carrying one of said stationarycontacts and extending toward the wall plate, a second bracket carryingthe other stationary contact and extending toward the wall plate, andresilient contact means on the wall plate, said contact means beingconnected to said terminals and arranged for engagement with saidbrackets when the cover is in place on the wall plate.

4. In a control device for mounting on a wall, the combination of, awall plate carrying terminals for electrical wirin and adapted to bemounted on a wall, a cover for the control device adapted for mountingon said wall plate, a

sub-base mounted on t e inside of the cover having one side f acing therear face of the cover and its other side facing the wall plate, acondition responsive device on the side of the sub-base facing the wallplate, said condition responsive device having one portion thereofsecured to said sub-base and actuating a movable electrical contact, afixed contact carried by the sub-base for cooperating with said movablecontact, first adjusting means extending through the cover forpermitting adjustment of the fixed contact from outside the cover,second adjusting means ex tending through the cover for shifting thecondition responsive device on the sub-base, and means for securing thecover to the wall plate and for connecting the contacts to the terminalson the wall plate.

5. In a control device for mounting on a wall, the combination of, acover adapted to be mounted on the wall, a sub-base mounted on theinside of the cover having one side facing the rear face of the coverand its other side facing the wall, a condition responsive devicemounted on the side of the sub-base facing the wall and actuating anelectrical contact, a stationary contact mounted on the sub-base andcooperating with.

the first mentioned contact. first adjusting means extending through thecover for permitting adjustment of the fixed contact from outside of thecover, and second adjusting means extending through the cover forshifting the condition responsive means on the sub-base.

6. In a control device for mounting on a wall, the combination of, acover adapted to be mounted on the wall, a sub-base mounted on theinside of the cover having one side facing the rear face of the coverand its other side facing the wall, a condition responsive devicemounted on the side of the sub-base facing the wall and actuating anelectrical contact, a stationary contact mounted on the sub-base andcooperating with the first mentioned contact, and adjusting means forthe control device, saidadjusting means comprising a shaft extendingthrough the cover and rotating a first a second shaft for posi-v tioninga portion of the control device and being rotated by a second lever, anda link connecting said levers, said link yieldably engaging the subbasefor holding the parts in adjusted position.

7. In a control device for mounting on a wall, the combination of, acover adapted to be mounted on a wall, a condition responsive devicemounted on the inside of the cover, a rotatable member for adjusting thecontrol device, a first lever for rotating said member, a rotatableadjusting member mounted on the cover and extending through the cover, asecond lever rotated by said adjusting member, and a link for connectingsaid two levers.

8. In a control device for mounting on a wall, the combination of, acover adapted to be mounted on a wall, a condition responsive devicemounted on the inside of the cover, a rotatable member for adjusting thecontrol device, a first lever for rotating said member, a rotatableadjusting member mounted on the cover and extending through the cover, asecond lever rotated by said adjusting member, and a link forconnectingsaid two levers, said link being resilient and having asurface thereof yieldably urged against a stationary surface for holdingthe parts in adjusted position.

9. In a control device, a base member, a condition responsive devicemounted on the base member, a rotatable member for adjusting the controldevice, a first lever for rotating said rotatable member, a rotatableadjusting member mounted on the base member, a second lever rotated bysaid adjusting member, and a link for connecting said two levers, saidlink yieldably engaging a relatively stationary surface for holding theparts in adjusted position.

10. In a control device for mounting on a wall, the combination of, anelongated cover adapted to be mounted on the wall, a thermostaticelement having one portion thereof mounted on the back of the cover,switching mechanism mounted on the back of the cover and controlled bysaid thermostatic element, a first adjusting means at one end of thecover and extending therethrough, said first adjusting'means including arotatable member accessible from the front of the cover and varying thecontrol point of the device, a second adjusting means at the other endof the cover and extending therethrough, said second adjusting meansvarying the effective differential of the instrument and including asecond rotatable member accessible from the front of the cover.

11. In a control device for mounting on a wall, the combination of, anelongated cover adapted to be mounted on the wall, a thermostaticelement having one portion thereof mounted on the back of the cover, amovable contact actuated by the thermostatic element, a fixed contactcooperating with said movable contact, means including a helical cammounted on the cover and facing the wall for adjusting the control pointof the instrument, and an operating member for rotating said helicalcam, said operating member extending through the front of cover so as tobe accessible from the front thereof.

12. In a control device for mounting on a wall, the combination of, anelongated cover adapted to be mounted on the wall, a thermostaticelement having one portion thereof mounted on the back of the cover, amovable contact actuated by the thermostatic element, a fixed contactcooperating with said movable contact, means including a helical cammounted on the cover and facing the wall for adjusting the control pointof the instrument, an operating member for rotating said helical cam,said operating member extending through the cover so as to be accessiblefrom the front thereof, means for adjusting said fixed contact to varythe operating differential of the control device, said last mentionedmeans including a second operating member extending through the cover.

HOMER E. MALONE.

